Swirly line bokeh on 400mm 2.8 IS

So I have a Canon 400mm f/2.8 IS paired with a 1D mark IIn and when I shot football today in very hot sunny clear sky weather, I get some strange "swirly" bokeh with individual lines in some of the photos. It sort of depends which angle I shoot at (as it seems to appear more on photos where the background includes the audience). I am not shooting behind a net or anything.

Very swirly bokeh
http://i174.photobucke​t.com …e/Photography/s​ample3.jpg

Little less swirlyness:
http://i174.photobucke​t.com …re/Photography/​sample.jpg

Can't see any swirly:
http://i174.photobucke​t.com …e/Photography/s​ample2.jpg

I shot soccer last week with the other body (the 1D mark II) in quite similarly sunny but not as hot weather and I didn't get this swirly effect. I'm not sure if the body is what's causing it.... probably not.

Soccer: http://www.flickr.com/​photos/siaohd/49343707​20/#/

Is this a normal phenomenon. All photos are f/2.8 and around 1/2000 shutter speed on AI SERVO. I used image stabilizer in football but I don't remember if I did for soccer. I am using the standard drop-in filter Canon gave me.

I looked up some of this occurrence and found this: http://www.bokehtests.​com …bilization_and_​Bokeh.html

Maybe IS should be turned off?

Try F4 and 5.6 and see what happens.....

filter?

Filters won't fit on the 400mm f/2.8 IS unless it's the drop-in filter.... I'm using the one Canon gave me.

heat distortion over certain parts of the stands/field?

Heat Haze

It looks like it has to do with your shutter speed. The first picture with the "Very swirly bokeh" is shot at 1/1,250 sec. The second picture with "Little less swirlyness" was shot at 1/1,600 sec. The third shot with "Can't see any swirly" was shot at 1/2,000 sec. The soccer shot was at 1/3200 sec. So I'm guessing the slower the shutter speed the more swirly bokeh your going to get.

Take Care,
Cheers, Patrick

If I refer to these speed informations, I guess it's IS with heat haze ..

I could never get better pictures with IS replacing the right speed !!! so, for two years now, I don't mind not to have IS on a lens. I really prefer to buy a fastest lens as possible than get a slow lens with IS.
I would say just for panning IS is missing a bit.

I would say its just heat haze.

My brand new 70-200 f/2.8 IS mark II displays similar bokeh but less pronounced at 200mm. I'm guessing it has to do with the hot weather and the grass was quite hot that day. I'll take the safety precaution and turn off IS the next time I shoot.

IS should have no effect one way or another.

Temperature (to some degree) and distance to subject (closer is cleaner) control how much of it you'll see. You can still have heat haze on cold days depending upon the ability of the surface to absorb and re-readiate the sun's energy. You can see a "mirage" on black asphalt in the winter.

it wouldn't change the type of lines with the shutter speed ... worst are with lower speed and bokeh became better with much higher shutter spped

I still imagine IS is tying to freeze something where it shouldn't ..

SiaoP wrote in post #10852643
My brand new 70-200 f/2.8 IS mark II displays similar bokeh but less pronounced at 200mm. I'm guessing it has to do with the hot weather and the grass was quite hot that day. I'll take the safety precaution and turn off IS the next time I shoot.

As others have said, IS won't do anything. It's just heat haze, there's nothing wrong with the lens.

Shot some soccer today. I did not see any of the convection effects on today's shots with or without IS. Setup is the same. The weather was 70F, partly cloudy. The pictures appear clearer I guess since theres no heat rising up from the ground. Bokeh much better now